NBRU general secretary Dermot O'Leary says employees see "no future" for the company as things stand.

And he has called on Transport Minister Paschal Donohoe to urgently get involved.

The second day of strike action yesterday forced about 100,000 commuters to take to buses and cars - crippling transport networks at rush hour.

Further stoppages are planned for September, but Mr O'Leary warned the possibility of an all-out stoppage cannot be ruled out, given that the union has a mandate of more than 80pc in favour of this action.

"As long as the company maintains the pay cuts, our members feel they have no alternative but to advance the dispute along the lines already decided," he told the Irish Independent.

He stressed that the situation would be reviewed on September 23."That mandate is there - and of course there is pressure. There is a certain element among our members that are saying to me: 'Don't forget we have that mandate'."

He also upped the ante with the Government, accusing Mr Donohoe of failing to do enough to end the impasse.

"The minister has a role to play and whether he personally intervenes is his own call. I'm very strong on this - he absolutely has a role to play. After all, he is a shareholder. He and his Government need to decide do they want a 2014 style railway system or not."

He described public support for the workers' action as "mixed".

"It's inevitable that people have been put out by the industrial action. But we would say the company are the cause of that - and not the union or the workers."

Keith Oglesey joined a group of 10 Irish Rail employees picketing at the side entrance to Connolly Station yesterday.

The train driver said there was growing appetite among a sizeable cohort of workers for immediate all-out strike action.

He said relations between frontline staff and management is at an all-time low, stemming from a deep mistrust fostered over many years.

"There's no goodwill left, because the company has been poorly managed, and that's why we're €147m in debt," he said. "Cost savings implemented by frontline workers since January have saved the company €37m."

But with no resolution to the dispute in sight, he believes an intervention is urgently needed by "someone from the Government".

"Otherwise this strike is only going one way, and it will escalate," he warned.

A spokesperson for the minister insisted the issues involved in the dispute needed to be resolved between the company and its employees. Junior Finance Minister Simon Harris also rejected calls for the government to intervene.

Mr Harris insisted all parties must engage in talks and avail of industrial relations mechanisms that are available.